Different lasers have heretofore been used to perform different types of tasks. For example, a modern microcircuit fabrication system employs pulsed Nd:YAG lasers to bond electrically conductive leads to electrical circuit contact pads. The pulsed Nd:YAG laser is capable of providing output pulses of between about ten microseconds and ten milliseconds in duration. The output pulse from a pulsed Nd:YAG laser output typically comprises a train of irregularly spaced subpulses of nonuniform shape and nonconstant power with decreasing amplitudes. A laser output pulse train of this type is suitable for bonding leads made of materials, such as tin-plated copper, that readily absorb the laser energy but is unsuitable for bonding leads made of materials, such as gold-plated copper, that reflect laser light.
Upon completion of a bonding operation, the microcircuit fabrication system employs a cutting mechanism, such as a reciprocating blade mechanism, to sever the leads from a lead frame to which the leads are attached.
A resistor trimming system uses a continuously pumped Q-switched Nd:YAG laser that creates a train of laser pulses to achieve a relatively slow removal of an electrically conductive target material. Each of the successive pulses in the pulse train effectively "nibbles"through about 10 percent of the target material.